Aluminum-humic colloid formation during pre-coagulation for membrane water treatment: mechanisms and impacts.

Precoagulation has been widely used by low pressure membrane filtration (LPMF) plants to reduce membrane fouling and increase natural organic matter (NOM) removal. Formation of aluminum and aluminum-NOM moieties plays a fundamental role in this important water treatment process. This study comprehensively investigated the mechanisms of aluminum-NOM species formation during precoagulation and their impacts on LPMF performance.

Static and dynamic removal of aquatic natural organic matter by carbon nanotubes.

Carbon nanotubes (CNTs) were investigated for their capability and mechanisms to simultaneously remove colloidal natural organic matter (NOM) and humic substances from natural surface water. Static removal testing was conducted via adsorption experiments while dynamic removal was evaluated by layering CNTs onto substrate membranes and filtering natural water through the CNT-layered membranes. Analyses of treated water samples showed that removal of humic substances occurred via adsorption under both static and dynamic conditions.

Evaluating nanoparticle breakthrough during drinking water treatment.

Background: Use of engineered nanoparticles (NPs) in consumer products is resulting in NPs in drinking water sources. Subsequent NP breakthrough into treated drinking water is a potential exposure route and human health threat.

Objectives: In this study we investigated the breakthrough of common NPs--silver (Ag), titanium dioxide (TiO2), and zinc oxide (ZnO)--into finished drinking water following conventional and advanced treatment.

Toxicity of commercially available engineered nanoparticles to Caco-2 and SW480 human intestinal epithelial cells.

The effects of ingestion of engineered nanoparticles (NPs), especially via drinking water, are unknown. Using NPs spiked into synthetic water and cell culture media, we investigated cell death, oxidative stress, and inflammatory effects of silver (Ag), titanium dioxide (TiO2), and zinc oxide (ZnO) NPs on human intestinal Caco-2 and SW480 cells. ZnO NPs were cytotoxic to both cell lines, while Ag and TiO2 NPs were toxic only at 100 mg/L to Caco-2 and SW480, respectively.

Pilot study on effects of nanoparticle exposure on Crassostrea virginica hemocyte phagocytosis.

Little is known about engineered nanoparticles (NPs) exposures on oysters. As sessile filter feeders, oysters are likely to be exposed to NPs suspended in the water column with unknown effects of NP exposure on oyster functioning. Our study indicates that waterborne NPs alter oyster hemocyte phagocytosis dynamics, an indication of sub-lethal effects of NP exposures.

Persistence of triclocarban and triclosan in soils after land application of biosolids and bioaccumulation in Eisenia foetida.

The presence of the antimicrobial chemicals triclocarban (TCC) and triclosan (TCS) in municipal biosolids has raised concerns about the potential impacts of these chemicals on soil ecosystems following land application of municipal biosolids. The relative persistence of TCC and TCS in agricultural fields receiving yearly applications of biosolids at six different loading rates over a three-year period was investigated. Soil and biosolids samples were collected, extracted, and analyzed for TCC and TCS using liquid chromatography-tandem mass spectrometry.

Bioaccumulation of triclocarban in Lumbriculus variegatus.

The antimicrobial triclocarban (TCC) has been detected in streams and municipal biosolids throughout the United States. In addition, TCC and potential TCC transformation products have been detected at high levels (ppm range) in sediments near major cities in the United States. Previous work has suggested that TCC is relatively stable in these environments, thereby raising concerns about the potential for bioaccumulation in sediment-dwelling organisms.